Fins for swimmers



March 13, 1956 G. CRESSI ET AL FINS FOR SWIMMERS Filed Aug. 31, 1953 IN V EN TOR.5

MFA/E y United States Patent FINS FOR SWIMMERS Giovanni Cressi and Luigi Ferraro, Genoa, Italy Application August 31, 1953, Serial No. 377,630 1 Claim. (Cl. 9-21) Fins for the purpose of increasing elficiency in swimming are already known, but the devices of this kind at present in use have the serious disadvantage of requiring a bigger efiort on the part of the swimmer and of alfording less efiiciency than it could reasonably be expected. As a matter of fact in present day fins the angle formed by the axis of the fin and by that of the tibia of the swimmer is excessively narrow, thereby causing loss of efficiency due to the attrition which takes place with respect to the direction of swimming, since it is evident that the ideal position of maximum efiiciency is that corresponding to the widest angle between the ideal axis of the tibia and that of the fin. Moreover, the fins known at present are so shaped that the point on which the force acts on the foot is too distant from the ankle, entailing a long lever-arm and, consequently, discomfort of the foot and of the ankle of the swimmer. Also, present day fins constrict the foot, particularly the forward portion of it in a sort of shoe which does not permit free movement of the toes, causing further discomfort to the wearer.

The improvements according to the invention consist in the construction of a fin for swimmers which overcomes the above mentioned inconveniences, and having a shape as will entail the smallest possible passive stress in relation to the task it has to perform.

in fact, the fin according to the present improvements is shaped in such a Way that it forms with the ideal axis of the tibia a much wider angle than in the case of other models, with great advantage for the swimmer. Furthermore, the fin according to the present invention leaves the toes uncovered, ensuring their freedom of movement, avoiding the above mentioned constriction and discomfort and permitting the expulsion of sand, grit and the like. Lastly, the fin according to the present invention is provided with rounded edges for the purpose of reducing to a minimum the passive resistance of the water. The present invention is illustrated by way of example in the drawing herewith, in which:

Fig. l is the fin according to the improvements of the present invention,

Fig. 2 is a sectional view of Fig. 1,

Fig. 3 is the fin according to the invention, in working position and Fig. 4 is one of the known fins in working position, shown for the purpose of comparison with Fig. 3.

In said figures the fin according to the present invention is shaped in such a manner that at the back it has an appearance similar to that of a shoe, with buttress or heel section 1 for the heel in one piece with the sole 2, which forms an angle with the front fin portion 2'.

The fin according to the invention is provided with a housing 3 for the foot, the toes projecting through the opening 4. The borders or side portions 5 of the fin have rounded edges 6 and 7 suitably shaped for-the water to run along them with a minimum of attrition and passive resistance. These side portions form arcuately shaped lateral extensions of the foot portion. The borders 5 form lateral extensions of the foot portion and together with the front fin portion 2 form an increased fin area. It can be seen that since border portions 5 extend rearwardly to the heel section that a comparatively short lever arm is obtained thereby facilitating operation of the fin.

The fin according to the invention, conceived as above described, is as near as possible to the ideal fin, which should follow the line of axis A (Fig. 3), inasmuch as the angle P between said axis A and axis A is much wider than the angle K formed in ordinary fins (Fig. 4) by axis A and axis S. The point 8 on which the force acts on the foot (Fig. 3), is much nearer to the ankle than point 9 (Fig. 4) which in the known types is located near the metatarsus.

The functioning of the fin according to the present invention is made evident by Fig. 3. For the reasons mentioned above, said functioning provides a much higher degree of efiiciency than other similar devices inasmuch as swimming is made swifter with less efiort. The fin fits the foot comfortably and is subject to less resistance owing to its particular shape which permits the water to slide, so to speak, along the rounded edges, without creating the right angle resistance offered by fiat fins. Furthermore, the shape of the sole further increases efiiciency inasmuch as it ofiers two planes of adherence to the foot and consequently provides a more efiicient use of the effort of the foot.

The fin described above may in practice be subject to some modifications in shape and of angles. The invention therefore is not to be restricted except in so far as is necessitated by the spirit of the appended claim.

We claim:

A fin for a swimmer comprising a foot portion having an integral upwardly extending heel section and an open toe section, an elongated fin portion integrally formed on said foot portion, said fin having side portions forming arcuately shaped lateral extensions of the foot portion, said side portions extending rearwardly to a point immediately adjacent the heel section, and a front fin portion integrally formed with the open toe section of the foot portion and the side portions of the fin, said fin extending at an angle with respect to the longitudinal axis of said foot portion.

References Cited in the file of this patent UNITED STATES PATENTS Re. 23,006 Churchill June 15, 1948 D. 132,377 Smith May 12, 1942 2,099,973 Corlieu Nov. 23, 1937 FOREIGN PATENTS 819,804 Germany Nov. 5, 1951 1,014,738 France Aug. 20, 1952 

